The conductive paste containing mainly metal powder as solid content has been widely used in electronic device components since it shows excellent conductive properties and for example, is used as material for an electrically-conductive path when forming an electric circuit on a wiring board. As this conductive paste, a conductive paste produced in a paste state by dispersing, for example metal powder and glass frit, in an organic vehicle is available. Then, the conductive paste is applied to a ceramic, glass substrate or the like by screen printing or the like so as to form a wiring pattern. Next, when the conductive paste is sintered at high temperatures, the organic vehicle is transpired and the metal powder is sintered so as to form a continuous film. Such conductive paste provides excellent conductive properties since the metal powder is sintered to form the continuous film.
To achieve high density in electronic device components using the conductive paste, fine wiring patterns (or fine patterns) need to be formed efficiently. Patent Document 1 has disclosed a conductive paste for improving the accuracy of fine pattern to be formed.
Patent Document 1 discloses a conductive paste in which the viscosity (V1rpm) under a rotational speed of rotations of 1 rpm measured using a No. 4 spindle of a Brookfield rotating viscometer is 200 Pa·s or more, and the ratio (V1rpm/V10rpm) between viscosity V1rpm under a rotational speed of 10 rpm and viscosity V10rpm is 2-5. The use of the conductive paste having such viscosity characteristics makes it hard for conductive paste applied in a predetermined pattern to droop down, thereby securing excellent shape maintainability. In this conductive paste, the ratio of conductive power occupying the conductive paste is preferably 80-95 wt %. Also, the use of such conductive paste improves the shape accuracy of the fine pattern without degrading handleability and printability of the conductive paste.    Patent document 1: Japanese Laid-Open Patent Publication No. 2004-139838